/**
 * Copyright (C) 2008 Google Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.google.inject.internal;

import com.google.inject.TypeLiteral;
import com.google.inject.internal.util.SourceProvider;
import com.google.inject.matcher.AbstractMatcher;
import com.google.inject.matcher.Matcher;
import com.google.inject.matcher.Matchers;
import com.google.inject.spi.TypeConverter;
import com.google.inject.spi.TypeConverterBinding;

import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.Type;

/**
 * Handles {@code Binder.convertToTypes} commands.
 *
 * @author crazybob@google.com (Bob Lee)
 * @author jessewilson@google.com (Jesse Wilson)
 */
final class TypeConverterBindingProcessor extends AbstractProcessor {

    TypeConverterBindingProcessor(Errors errors) {
        super(errors);
    }

    /** Installs default converters for primitives, enums, and class literals. */
    static void prepareBuiltInConverters(InjectorImpl injector) {
        // Configure type converters.
        convertToPrimitiveType(injector, int.class, Integer.class);
        convertToPrimitiveType(injector, long.class, Long.class);
        convertToPrimitiveType(injector, boolean.class, Boolean.class);
        convertToPrimitiveType(injector, byte.class, Byte.class);
        convertToPrimitiveType(injector, short.class, Short.class);
        convertToPrimitiveType(injector, float.class, Float.class);
        convertToPrimitiveType(injector, double.class, Double.class);

        convertToClass(injector, Character.class, new TypeConverter() {
            public Object convert(String value, TypeLiteral<?> toType) {
                value = value.trim();
                if (value.length() != 1) {
                    throw new RuntimeException("Length != 1.");
                }
                return value.charAt(0);
            }

            @Override
            public String toString() {
                return "TypeConverter<Character>";
            }
        });

        convertToClasses(injector, Matchers.subclassesOf(Enum.class), new TypeConverter() {
            @SuppressWarnings("unchecked")
            public Object convert(String value, TypeLiteral<?> toType) {
                return Enum.valueOf((Class) toType.getRawType(), value);
            }

            @Override
            public String toString() {
                return "TypeConverter<E extends Enum<E>>";
            }
        });

        internalConvertToTypes(injector, new AbstractMatcher<TypeLiteral<?>>() {
            public boolean matches(TypeLiteral<?> typeLiteral) {
                return typeLiteral.getRawType() == Class.class;
            }

            @Override
            public String toString() {
                return "Class<?>";
            }
        }, new TypeConverter() {
            @SuppressWarnings("unchecked")
            public Object convert(String value, TypeLiteral<?> toType) {
                try {
                    return Class.forName(value);
                } catch (ClassNotFoundException e) {
                    throw new RuntimeException(e.getMessage());
                }
            }

            @Override
            public String toString() {
                return "TypeConverter<Class<?>>";
            }
        });
    }

    private static <T> void convertToPrimitiveType(InjectorImpl injector, Class<T> primitiveType, final Class<T> wrapperType) {
        try {
            final Method parser = wrapperType.getMethod("parse" + capitalize(primitiveType.getName()), String.class);

            TypeConverter typeConverter = new TypeConverter() {
                @SuppressWarnings("unchecked")
                public Object convert(String value, TypeLiteral<?> toType) {
                    try {
                        return parser.invoke(null, value);
                    } catch (IllegalAccessException e) {
                        throw new AssertionError(e);
                    } catch (InvocationTargetException e) {
                        throw new RuntimeException(e.getTargetException().getMessage());
                    }
                }

                @Override
                public String toString() {
                    return "TypeConverter<" + wrapperType.getSimpleName() + ">";
                }
            };

            convertToClass(injector, wrapperType, typeConverter);
        } catch (NoSuchMethodException e) {
            throw new AssertionError(e);
        }
    }

    private static <T> void convertToClass(InjectorImpl injector, Class<T> type, TypeConverter converter) {
        convertToClasses(injector, Matchers.identicalTo(type), converter);
    }

    private static void convertToClasses(InjectorImpl injector, final Matcher<? super Class<?>> typeMatcher, TypeConverter converter) {
        internalConvertToTypes(injector, new AbstractMatcher<TypeLiteral<?>>() {
            public boolean matches(TypeLiteral<?> typeLiteral) {
                Type type = typeLiteral.getType();
                if (!(type instanceof Class)) {
                    return false;
                }
                Class<?> clazz = (Class<?>) type;
                return typeMatcher.matches(clazz);
            }

            @Override
            public String toString() {
                return typeMatcher.toString();
            }
        }, converter);
    }

    private static void internalConvertToTypes(InjectorImpl injector, Matcher<? super TypeLiteral<?>> typeMatcher, TypeConverter converter) {
        injector.state.addConverter(new TypeConverterBinding(SourceProvider.UNKNOWN_SOURCE, typeMatcher, converter));
    }

    @Override
    public Boolean visit(TypeConverterBinding command) {
        injector.state.addConverter(new TypeConverterBinding(command.getSource(), command.getTypeMatcher(), command.getTypeConverter()));
        return true;
    }

    private static String capitalize(String s) {
        if (s.length() == 0) {
            return s;
        }
        char first = s.charAt(0);
        char capitalized = Character.toUpperCase(first);
        return (first == capitalized) ? s : capitalized + s.substring(1);
    }

}
